# A solution of ammonia and water contains 1.40xx10^25 water molecules and 6.30xx10^24 ammonia molecules. How many total hydrogen atoms are in this solution?

$2 \times 1.40 \times {10}^{25} + 3 \times 6.30 \times {10}^{24}$ $=$
$\text{How many hydrogen atoms?}$
We have $1.40 \times {10}^{25}$ water molecules, and $6.30 \times {10}^{24}$ ammonia molecules. Given that for each water molecule there are $2 \times H \text{ atoms}$, and for each ammonia molecule there are $3 \times H \text{ atoms}$, I make the number $2 \times 1.40 \times {10}^{25} + 3 \times 6.30 \times {10}^{24}$ $=$ ??